text: Subsequent to its invention by Dimitri Sensaud deLavaud, a French-Brazilian, in 1918, much cast iron pipe manufacturing shifted to the dramatically different technique of centrifugal casting.  Modern ductile iron pipe production continues to use this general method of casting.
  Historically, two different types of molds have been used in centrifugal casting of cast iron pipe: metal molds and sand molds.  With metal molds, molten iron was introduced into the mold to uniformly distribute metal over the interior of the mold surface by the centrifugal force generated.  The outside mold was typically protected from damage by a controlled water bath or water spray system.  When the pipe was cool enough to be handled and hold its shape, the mold was stopped and the pipe removed.  Pipe formed in metal molds were typically annealed after casting to eliminate any stresses in the pipe, and were then cleaned, inspected, tested, gauged (for dimensions), coated internally and/or externally, and stored for use.  Standards for cast-iron pipe centrifugally cast in metal molds for water were established and published by the American Water Works Association.
  When cast with sand molds, two types of manufacturing processes were used.  In the first method, a metal pattern was typically positioned in a metal flask and molding sand was rammed into the annular space between the flask and pattern.  The pattern was then removed for casting of the pipe using molten grey iron.  The second method did not entail a metal pattern, but entailed the forming of the mold centrifugally by lining the heated flask with a measured amount of thermosetting resin and sand.  Either way, the casting machine was stopped after the pipe had solidified and the flask was removed.  Cast iron pipe formed using this procedure was typically oven-cooled under controlled time and temperature conditions.  As with metal molds, pipe was typically annealed to eliminate any stresses in the pipe, and were then cleaned, inspected, tested, gauged (for dimensions), coated internally and/or externally, and stored for use.  Standards for cast-iron pipe centrifugally cast in sand molds for water were established and published by the American Water Works Association.